Robert b



R. B. SMITH.

PUMP.

APPLICATION FILED FEB. 6. 1919.

Patented Nov. 18, 1919.

INVENTOR M ROBERT B. SMITH, OF GRAFTON, PENNSYLVANIA.

PUMP.

Specification of Letters Patent.

Patented NOV. 18, 1919.

' Application filed February 6, 1919. Serial No. 275,392.

To all whom it may concern:

Be it known that I, ROBERT B. SMITH, a citizen of the United States, and a resident of Grafton, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Pumps; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to pumps and has special reference to air pumps.

The object of my invention is to provide a cheap, simple and efficient form of a pump, which will contain few parts, will be easy to manufacture, and will be capable of satis factorily performing its work at all times and under all conditions.

To these ends my invention consists, gen erally stated, in the novel arrangement, construction and combination of parts, as hereinafter more specifically set forth and described and particularly pointed out in the claims.

To enable others skilled in the art to which my invention appertains to construct and use my improved pump, I Wlll describe the same more fully referring to the accompanying drawing in which:

Figure 1 is a plan view showing my 11nproved pump and with the cylinder and piston in section;

Fig. 2 is a side elevation of the same;

Fig. 3 is an enlarged side view of the piston separated; and

Fig. 4 is an enlarged cross-sectlon of the piston showing the parts together in their operative position and taken on the line 44 Fig. 3, looking in the direction of the arrows.

Like symbols of reference herein indicate like parts in each of the figures of the drawis illustrated in the drawing A repre sents my improved pump, which is of the reciprocating type and is adapted to pump air at both strokes of the pistons hereinafter described. The pump A is mounted on a base 1 for supporting the same and is provided with a cylinder 2, having at each end of the same the usualoylinder heads 2. Within the cylinder 2 is the piston B which is formed in two sections by being split horizontally to form the intake piston member 3 and the delivery piston member 4, and such members are each provided with a hollow portion or chamber 5 having a semi-circular head 6 at each end of the same and a central portion 7 between the same. The peripheries of the heads6 bear against the inner wall of the cylinder 2 and the central portions 7 bear against and slide upon each other in the operation of the pump. Communicating with one side of the cylinder 2 is the air intake opening or pipe 8 which leads from the atmosphere, and leading from the opposite side of said cylinder and in line with said pipe is the opening or exhaust pipe 9,which has a flexible pipe (not shown) connected thereto and with any suitable storage tank. Connected to the front head 6 on the piston members 3 and 4 are the in-' take and delivery piston rods 10 and 11 respectively, which pass through suitable stuffing boxes 13 on the inner or front head 2 of the cylinder 2, and through the guide 14. Connected to the cross head 15 on intake piston rod 10 is the intake connecting rod 15 and connected to the cross head 16 on the delivery piston rod 11 is the delivery con necting rod 16, with such rod 15 being connected to a crank 17 on a crank shaft 17 and such rod 16 being connected to a crank 18 on said shaft. The intake crank 17 is arranged or set so that it will always be behind the delivery crank 18, which will place the delivery connecting rod 16, its piston rod 11 and member 4 in advance of the intake connecting rod 15, its piston rod 10 and mem ber 3. The crank shaft 17 is journaled in suitable bearings 19 on uprights or. standards 20 and a fiy-wheel 21 of suitable size and weight is mounted on one end of the said shaft. The delivery crank 18 and the intake crank 17 are movably connected together by means of the serrated faces 22 on each of the same meshing with each other and held in place by the adjusting bolt 22. Within and at each end of the central portion 7 of the intake piston member 3 are the ports 23, and within and at each end of the central portion 7 of the delivery piston member 4 are the ports 24, such ports 23 acting as inlet ports and the ports 24 acting as delivery ports in opening and closing at proper times in the operation of the pump A as hereinafter described. The members 3 and 4 of the piston B are provided with a suitable packing within the heads 6 and central portions 7, such as the leather strips 25 which fit within grooves 26 therein and act as the usual piston rings for these ports.

The use and operation of my improved pump A is as follows: The pump A is connected to an electric motor or other source of power in any, suitable manner, such as by a belt (not shown) passing over the pulley 21, so that when the air is drawn into the cylinder 2 through the pipe 8, such itlhWlll. enter the chamber 5 of the intake piston member 3 if the pump is to be operated in the direction indicated by the arrow on the fly-wheel 21 in Fig. 2, and upon such member being forced forwardly the air 1n such chamber will pass out through the rear port 23 in such chamber and into the rear end of the cylinder, thereby throwing forward the crank-shaft 17 connected to said member through the rods 10 and 15. It will be obvious that the crank-shaft 18 is always 111 advance or ahead of the crank shaft 17 and therefore the delivery piston member 4 through its rods 11 and 16 connecting with said crank-shaft 17, so that as such member 3 moves forward it will cause the air in the front end of the cylinder 2 to be forced into the chamber 5 of the member 4 through the front port 24therein and thence to the. storage tank through the delivery pipe 9, and by reason of the moving forward of said memher 3 and compressing such air in the front end of the cylinder, the member 4 is forced backward. As the member 4 is thus forced backward, the air entering the chamber 5 of the member 3 through the pipe Swill pass through the front port 24 of the member 3 into the front end of the cylinder 2 and the air in the rear end of the cylinder will pass through the rear port 24 in the member 4 into the chamber 5 thereof and thence out through the pipe 9 to the storage tank. These operations are thus continued with the air constantly entering the chamber 5 of the piston member 3 through the pipe 8 and entering the rear and front ends of the cylinder 2 alternately through the rear and front ports 23 in said member, while the air from the front and rear end of such cylinder is discharged alternately through the front and rear ports 24 into the chamber 25 of the piston member 4 and thence through the pipe 9 to the storage tank. The ports 23 act as inlet ports and the ports 24 thus act as delivery ports and in case it is desired to operate the pump A in the opposite direction from that shown by the arrow on the fly wheel in Fig. 1, the operations will still remain the same with the delivery member 4 acting as intake member 3 and the intake member acting as the delivery member. In such reversal of direction of operation, the delivery member will still be in advance of the intake member with the pipe 9 supplying the air and the pipe 8 exhausting the same, and when in operating in either direction all the ports or valves at dead centers are closed.

lVith the ports 23 in the intake piston member-3 thus acting as sliding valves they will be opened and closed at the proper time to permit a continuous flow of air into the cylinder 2, and with the ports 24 1n the member 4 thus acting as delivery valves, such valves are also opened and closed at the proper time. On the first half of the strokeof the members 3 and 4 one intake port 23 and one delivery port 24 are gradually closed, while on the second half of the stroke of said members such opening and closing of the ports are reversed.

In case it is desired to adjust the cranks 17 and 18 to satisfy operating conditions, the bolt 22 is simply loosened and the crank shifted on their serrated faces 22 to the desired positions, after which the bolt is then tightened and the cranks held in their shifted positions.

It will thus be seen that my improved pump is of the reciprocating type, it will pump air on both strokes of the piston, and by reason of there being an air chamber in the delivery piston a steady flow of air will result, and there being also an air chamber within the intake piston it will tend to keep the cylinder cool, while the shifting of the crank-shafts will make the pump suitable for any kind of work, such as pumping up an automobile tire which should be rather slow, to pumping up a storage tank, which should be of a much faster nature.

It will further be seen that any size motor can be used to operate the pump, as the power required is proportional to the amount of air pumped, while the air to be pumped in unit time can be adjusted by the shifting of the cranks, which means that you can adjust the pump to deliver air at the rate of a full cylinder per stroke down to Zero air per stroke of pistons. The shifting of the cranks can be made to any position with respect to each other, and by changing the setting of the cranks a considerable variation in the volume of air pumped in unit time can be obtained, such as a full cylinder, a half cylinder, a quarter cylinder or whatever amount of air desired can be pumped during each stroke of the piston.

Various modifications and 'changesin the design and construction of my improved pump may be resorted to without departing from the spirit of the invention or sacrificing any of its advantages.

lVhat I claim as my invention and desire to secure by Letters Patent is:

1. An air pump comprising a cylinder having air intake and delivery openings, a split piston within said cylinder formed of two members adapted to slide upon each other and provided with ports arranged to suitably control the passage of air through the members, a crap. shaft and two cranks mountedthereon and a connection between each crank and one of said members, said cranks being secured to the shaft one in advance of the other to a sufficient degree to cause the piston members to move in the same direction during a part of each stroke and to move in the opposite direction when near the end of each stroke, whereby said ports are controlled 2. An air pump comprising a cylinder having air intake and delivery openings, a split p'iston within said cylinder formed of two members adapted to slide upon each other and provided with ports arranged to suitably control the passage of air through the members, a crank-shaft and two cranks mounted thereon and a connection between each crank and one 0]": said members, said cranks being secured to the shaft one in advance of the other to a sufiicient degree to cause the piston members to move in the same direction during a part of each stroke and to move in the opposite direction when near the end of each stroke, whereby said ports are controlled, and means connected to said cranks for shifting the relative positions of the same.

3. An air pump comprising a cylinder having air intake and delivery openings, a

split piston within said cylinder formed of two members adapted to slide upon each other and provided with ports arranged to suitably control the passage of air through the members, a crank-shaft and two cranks mounted thereon and a connection between each crank and one of said members, said cranks being secured to the shaft one in advance of the other to a sufiicient degree to cause the piston members to move in the same direction during a part of each stroke and to move in the opposite direction when near the end of each stroke, whereby said ports are controlled, serrated faces on said cranks for engaging with each other, and an adjusting bolt passing through each of said cranks and faces for shifting the relative positions of said cranks.

In testimony whereof, I, the said ROBERT E. SMITH, have hereunto set my hand.

ROBERT B. SMITH.

Witnesses:

J M. GEOGHEGAN, J. N 000KB. 

